I think you should just jump into it like a Japanese kamikaze. There are so many IF's. You won't be able to answer your questions until you give it a shot. What if your feeling is mutual and he's a great guy who would never cheat on you but you missed out on him because you were scared to take the leap.
Well, those kinds of things can happen in any relationship, right? It's not a new concept or unique only to you. There are just as many what ifs on the positive side, like what if they are a genuinely good person? Nothing ventured nothing gained.